An isolated measurement system typically includes a measurement system to measure external signals and a control system to control the measurement system and receive measurement data therefrom. The two systems operate in two different voltage domains that are galvanically isolated from each other. The measurement system often includes multiple channels, each with its own measurement system and converter. Each channel transmits sampled data, in an asynchronous manner, to the control system through a respective data communication transformer.
A power generator provided in a voltage domain of the control system generates power for a voltage domain of the measurement system. The power generator includes a power transmitter in the control system's domain coupled to a rectifier in the measurement system's domain via a transformer that bridges an isolation barrier between the two domains. The power transmitter and rectifier are active continuously to ensure power supply to the measurement system is continuous. A power monitor may measure a voltage supply provided by the rectifier and may generate power feedback data therefrom, which is communicated to the control system's domain via a dedicated isolation transformer.
Modern applications of isolated measurement systems provide separate signaling paths for measurement data and power feedback data within the system. Thus, measurement systems may generate data that is communicated across an isolation barrier through a first set of isolators, typically one isolator per measurement channel. Power monitors may generate power feedback information that may be communicated across the isolation barrier through another isolator. Isolator devices, however, consume significant area and cost when the systems are manufactured. The inventors have identified a need for such a system in which communication of power feedback data makes efficient use of isolators and minimizes area and cost.